Search and directed synthesis of highly effective and safe antibacterial agents is one of the primary tasks of modern pharmacology and medical chemistry. In recent years there has been a marked increase in the number and prevalence of infectious diseases caused by the emergence of new highly pathogenic strains of microorganisms and an increase in their resistance to existing antibiotics.
Despite the presence of episodically occurring acute bacterial infections, for example, caused by mutated strains of Escherichia coli (O104: H4), one of the main causes of death in developed countries remain well-known bacteria—Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. 
In particular, according to the WHO, Staphylococcus aureus tops the list of bacteria that are most frequently cause infection in medical institutions. Methicillin-resistant strains of Staphylococcus aureus, which cause sepsis and severe forms of skin and soft tissue infections (furunculosis, phlegmon, scalded skin syndrome), are a particular danger to humans, causing up to 31% of patients to die.
One of the most effective antibacterial preparations used in modern practice for the suppression of methicillin-resistant strains of Staphylococcus aureus are fluoroquinolone preparations, in particular, ciprofloxacin. According to the chemical structure, ciprofloxacin is a fluoroquinolone derivative.
The mechanism of its action is to suppress bacterial DNA gyrase (topoisomerase II and IV, responsible for the supercoiling of chromosomal DNA around nuclear RNA, which is necessary for reading genetic information), impair DNA synthesis, growth and division of bacteria, which causes pronounced morphological changes (including in cell wall and membranes) and rapid death of a bacterial cell.
Ciprofloxacin has an antibacterial effect with the greatest activity against a number of aerobic gram-negative and gram-positive bacteria, namely: Pseudomonas aeruginosa, Haemophilus influenzae, Escherichia coli, Shigella spp., Salmonella spp., Neisseria meningitidis, N. Gonorrhoeae, Staphylococcus spp. (producing and not producing penicillinase), some strains of Enterococcus spp., as well as Campylobacter spp., Legionella spp., Mycoplasma spp., Chlamidia spp., Mycobacterium spp [Yakovlev V. P. Antibacterialnye preparaty gruppy ftorchinolov [Antibacterial drugs of the fluoroquinolone group]/Rus. med. journal—1997, Vol. 0.5—p. 1405-1413.].
Ciprofloxacin is used in infectious and inflammatory diseases caused by microorganisms susceptible to ciprofloxacin, including diseases of the respiratory tract, abdominal cavity and organs of the pelvis, bones, joints, skin, septicemia, severe infections of ENT-organs, etc. [Sárközy G. Quinolones: a class of antimicrobial agents/Vet. Med.—2001—V. 46—P. 257-274].
A significant drawback of ciprofloxacin is the restriction of intake by age —prescription of this drug is contraindicated in children and adolescents, as it causes a growth disorder [Beloborodova N. V, Padeyskaya E. N., Biryukov A. V. Ftorquinolony v pediatrii—za i protiv [Fluoroquinolones in pediatrics—pros and cons]/Pediatrics Publ. —1996. Vol. 2.—P. 76-84.].
Also, the disadvantages of ciprofloxacin include quite common side effects of the drug—abdominal pain, nausea, dysbiosis, insomnia, dizziness, allergic reactions (angioedema, urticaria, pruritus). In recent years, there has been a significant increase in the resistance of microorganisms to the entire class of fluoroquinolones [Norrby S. R. Side-effects of quinolones: comparisons between quinolones and other antibiotics/Eur. J. Clin. Microbiol. Infect. Dis.—1991—V.10—P. 378-383].
As the effective filing date of the claimed invention it is known that most methicillin-resistant staphylococci are resistant to cyprofloxacin [Lowy F. D. Antimicrobial resistance: the example of Staphylococcus aureus/J. Clin. Invest.—2003—V. 111.—P. 1265-1273.].
The study of the relationships of structure-biological activity in a series of ciprofloxacin derivatives revealed that the nature of the substituent at the C-7 atom has the greatest influence on their biological action [Emamia S., Shafiee A., Foroumadi A. Quinolones: Recent Structural and Clinical Developments/Iran. J. Pharm. Res.—2005.—V.-P. 123-136].

Most often, such substituents are five- and six-membered nitrogen-containing heterocycles, such as piperazine, pyrimidine, 1,2,3-triazole, pyrrolidine, and their substituted derivatives.
The source [N. German, P. Wei, G. W. Kaatz and R. J. Kerns. Synthesis and evaluation of fluoroquinolone derivatives as substrate-based inhibitors of bacterial efflux pumps/Eur. J. Med. Chem.—2008—V. 43. —P. 2453-2463] describes ciprofloxacin derivatives modified at the C-7 atom of the piperazine ring by fragments of various peptides and substituted diarylureas. These compounds showed slightly lower antibacterial activity compared to ciprofloxacin.
Modification of ciprofloxacin by the C-7 atom of the piperazine ring with an aminoglycoside antibiotic neomycin through a bridge containing a 1,2,3-triazole fragment resulted in hybrid structures exhibiting high antibacterial activity against strains of gram-negative and gram-positive bacteria [V. Pokrovskaya, V. Belakhov, M. Hainrichson, S. Yaron and T. Baasov Design, Synthesis, and Evaluation of Novel Fluoroquinolone-Aminoglycoside Hybrid Antibiotics/J. Med. Chem.—2009—V. 5. P, 2243-2254].
An international application [WO2011034971A1. Modified fluoroquinolone compounds and methods of using the samee/Designmedix, Inc. —Publ. on Mar. 24, 2011] describes ciprofloxacin derivatives by the C-7 atom of the piperazine ring, significantly exceeding its antibacterial activity against strains of gram-positive and gram-negative bacteria.
It should be noted that a significant disadvantage of all the above compounds is their high toxicity, which does not allow them to be considered as candidates for antibacterial preparations.